Laserfiche WebLink
<br />I I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />41 <br /> <br />V. SELECTED PLAN <br />As a result of the discussions with the project sponsors, it was decided <br />to develop a plan which would convey the five-year developed condition runoff, <br />and to provi de for an overflow mechani sm in the 100-year event. The develop- <br />ment of a five-year system is in general accordance with the "Draft Street and <br />Storm Drainage Criteria Manual", prepared as part of this project. 100-year <br />conveyance has been proposed along Railroad Avenue. <br />The general focus on the Selected Plan is to implement the diversion con- <br />cept, as generally shown on Figure 9. This plan would effectively prevent <br />flows from entering the Central Basin, by means of diverting runoff in pipes <br />and/or channel s to the Town of Ordway Ditch on the east, and an improved chan- <br />nel adjacent to County Road 17 on the west. This diversion eliminates the <br />need to reconstruct the existing box culvert at City Park, and will eliminate <br />the ponding and inadequate positive drainage along the railroad right-of-way. <br />The Selected Plan has been presented on Figure 10 (contained in map <br />pocket). The improvements shown on the drawings are subject to final design <br />engineering prior to construction, but provide a preliminary level of design <br />data for the major drai nage facil ities proposed for the Town of Ordway. A <br />cost estimate of the improvements has been presented on Table 13. <br />In order for the system to operate properly and to 1 imi t the potenti a1 <br />for flooding in areas downstream of the P1anning"Area, offsite improvements <br />have been developed. The offsite improvements generally consist of open chan- <br />nels along the historic channels heading to Bob Creek and Lake Meredith. The <br />offsite improvements have been shown on Figure 11. Table 14 presents a sum- <br />mary of construction costs for the offsite systems. <br /> <br />Implementation Alternatives <br />The cost presented on Table 13 has been calculated using reinforced <br />concrete pipe as the primary means of conveyance, which in practice is not the <br />only material available to the Town. Polyvinyl-chloride pipe (PVC) can be <br />used for all storm sewers less than 42-inches in diameter. Besides a 20 per- <br />cent decrease in installation costs, installation by Town forces is also <br />enhanced. Use of PVC storm sewer could result in a savings of approximately <br />$150,000. <br /> <br />-A <br />